The invention applies to means for transporting loads. The device is advantageously designed to lift vertically and to transport horizontally, principally in competition with the lifting means of “lighter-than-air” aircraft such as dirigible balloons.
Very numerous V/STOL aircraft proposals have already been put forward. However, apart from helicopters, tilt rotor aircraft and a few military aircraft using jet deflection, such as the “Harrier”, or additional lift units for take-off and landing, these proposals have not encountered the expected success. There has also been, over the past few years, a renewal of interest in craft with ducted-fans integrated into the structure of said craft.
The lack of commercial success of these aircrafts stems from the fact that they all suffer from major drawbacks, which include:                1. their low lifting capacity, which generally constrains them to use motive powers greater than would be necessary for cruising flight: this applies to helicopters, military aircraft, ducted-fan aerodynes;        2. their high price, which is a result of the aforementioned drawback, and which leads to the use of costly gas turbines to save weight in the drive system: this is the case of helicopters and ducted-fan aerodynes;        3. the danger of proximity to a rotating unprotected fan: this is the case with helicopters and tilt-rotor aerodynes, and        4. the difficulty of managing the transition phase between vertical flight and horizontal flight: this is the case of tilt-rotor and/or ducted-fan aerodynes.        
To increase the vertical lift force of the lift/propulsion devices equipping V/STOL aerodynes, there have already been proposed, with some efficacy, airfoil “blowing” means. In these proposals, some or all of a flow of gas generated by a gas generator such as a gas turbine, for example, is “blown” over wings to generate a high vertical lift force under these conditions. This is the case in particular of the proposals set out in the following patent documents.
U.S. Pat. No. 4,447,028, in which direct blowing by turbojets of an aerodyne onto the extrados of the high-camber wings of the aerodyne enables the take-off distance to be shortened, but does not allow vertical take-off or landing.
U.S. Pat. Nos. 3,124,323, 3,276,723, 3,785,592, 5,054,713, 5,170,963 and 6,382,560 (among numerous further examples) all describe devices with a circular structure, like “flying saucers”, in which one or more gas generators integrated into the structure blow a stream of air over peripheral airfoils, which are annular or disposed in a circle around the center of the structure. Some of these devices may be effective in developing a high vertical lift force but on the other hand all these devices have major disadvantages in horizontal flight, notably in respect of stability, resistance to forward movement (a high drag force is developed), the complexity of the mechanisms associated with the necessary mobility of the airfoils or at least parts of the airfoils, to go from one to the other of the various flight configurations, including most of all the transition between vertical flight and horizontal flight, and vice-versa. Like most of the other aforementioned patents in the same group, the aforementioned U.S. Pat. No. 5,170,963 describes a circular structure including airfoils with flaps disposed all around the circular support structure (see FIG. 1), these flaps being mobile and articulated by actuators so as to be able to move from a normal lift position (see FIG. 2A) to a high lift position (in a so-called “hyperlift” configuration, see FIG. 2B). It is clear, on examining the above patent, that to obtain a sufficient lift force the blown wings must be in a “hyperlift” configuration that will probably be satisfactory and sufficient for lifting the craft. However, knowing that in horizontal cruising flight these wings must return to a normal aerodynamic profile, and that their flaps must therefore be “retracted”, it is easy to anticipate difficult or even insurmountable problems in achieving an acceptable compromise between the lift necessary for the aerodyne to continue to fly and the drag of the profiles of the airfoils that brakes the aerodyne, without taking into consideration the drag of the actuators, such as rams, that maneuver the flaps, when the airfoil profiles are subjected to a crosswise airflow.
These are probably the reasons why the inventions described in the above patent documents have never led to concrete implementations observable in everyday life.
U.S. Pat. No. 5,503,351 describes a combination of circular devices such as those referred to above with a helicopter structure (see its FIG. 1) or an autogyro structure (see its FIG. 7). The weight of the device, and above all its complexity and the drag forces generated in cruising flight render this concept difficult to apply. The transition between vertical flight and horizontal fight would also be very difficult to manage.
U.S. Pat. No. 3,837,600 describes an airplane capable of flying in any direction with the aid of fans each driven in rotation in a respective duct to which are fastened respective lift airfoils, each of the blown ducted airfoil assemblies being pivoted, at the front, in the middle and at the rear of the aircraft and laterally on either side of the cell of the aircraft, about a fixed axis inclined from top to bottom and from the outside toward the inside in a plane parallel to the plane defined by the pitch and yaw axes, with synchronized control of pivoting of the assemblies mounted at the front and in the middle of the aircraft. This proposal has the major drawback of the very high drag induced by the pivoting assemblies and the production cost and complexity and weight of the mechanisms for synchronized pivoting of said assemblies.
GB 951,186 and GB 2,321,227 disclose lift and propulsion devices for a VTOL or V/STOL aerodyne employing the lift effect obtained by blowing a stream of air produced by an airflow generator over lift airfoils connected to a lifting structure of the aerodyne, the device comprising two longitudinal, substantially rectilinear airfoils disposed on either side of the support structure and extending substantially parallel to the roll axis of the device, the two longitudinal airfoils being symmetrical to each other with respect to the plane defined by the roll and yaw axes. In this way the force of resistance to forward movement (aerodynamic drag) of these longitudinal airfoils is minimized when the device moves horizontally in the direction of its roll axis, which is its main axis.
Nevertheless, the ability to generate sufficient lift by means of such lifting devices is doubtful, for which reason, in the aforementioned patent documents, other more conventional lift and propulsion devices are provided, and are substituted for or combined with them.